What is the difference between primary key and natural key?

What is the difference between primary key and?

Both Primary key and Unique Key are used to uniquely define of a row in a table. Primary Key creates a clustered index of the column whereas a Unique creates an unclustered index of the column . A Primary Key doesn't allow NULL value , however a Unique Key does allow one NULL value .

What is the difference between surrogate key and natural key?

A Primary Key can be either a single column using a surrogate (meaningless) number (a.k.a. Surrogate Key) or a column or set of columns that have meaning to the user and uniquely identify a row in a table (Natural Key).

What is an example of a natural key?

For example if there is a table storing the information about US citizens, the Social Security Number would act as the natural key, Social Security Number being the natural key might pose a problem in the future if the US government changes the structure of the Social Security Number and increases the number of digits ...

What is a natural key in DBMS?

In data warehouse tables, natural keys are meaningful values that identify records, such as social security numbers that identify specific customers, calendar dates in a time dimension, or SKU numbers in a product dimension. In some cases, natural keys are unique identifiers and can serve as primary keys.